1. Field of the Invention
The present invention generally relates to a self-cleaning system for a disk drive recording head, and more particularly, to a cleaning zone having an abrasive surface that is located on the disk surface to mechanically clean the recording head as it passes over the cleaning zone.
2. Description of the Related Art
Computer disk drive technology evolution has focused on improvements in "areal density", that is, the number of bits of information that can be stored in a given space on a magnetic disk. Over the last decade, the majority of progress has been gained through miniaturization of the recording heads and improving the magnetic efficiency of the write/read elements in the heads, and similar improvements in the magnetic and physical properties of the disks.
Disk drives contain a plurality of recording heads that "fly" over rotating disks. The magnetic recording efficiency is a function of many physical characteristics of the heads and disks, the most significant of which is the spacing between the rotating disk surface 4 and the recording head 2 "pole" elements 6 as shown in FIG. 1. The most straightforward method for manufacturers to improve areal density has been to reduce the spacing between the head 2 and disk 4, without sacrificing the long term reliability of the disk drive.
Across the previous disk drive industry product offerings, head-disk spacing had steadily decreased from several micro-inches to less than two micro-inches, until there came a point that further increases in areal density required the head to essentially touch the disk during flying. A new class of so-called "pseudo-contact" heads were developed in which the rear portion of the head, where the transducer poles 6 are located, is in constant contact with the disk surface. Various design characteristics were developed to minimize friction and wear between the disk and head, and such "pseudo-contact" designs have proven to be as reliable over the long-term as the non-contact designs.
A problem arises, however, when foreign material or particles come between the head poles and the disk surface, causing a "spacing loss" that affects the magnetic recording process. The types and sources of the foreign material are numerous, including; particles generated by mechanical motion of components inside the drive, contamination introduced at the time of manufacture, and build-up of excessive lubricant from the disk surface onto the poles of the head. The build-up of contaminants can temporarily increase the spacing between the disk and the recording head, degrading the disk drive performance. Another disadvantage is that contaminants may fall from the recording head during the stop cycles, creating enough friction between the head, the disk and the contaminants that a disk drive motor can no longer move the recording head at the commencement of the start cycle.
Great care is taken to remove sources of contamination during assembly, and in the design and fabrication of components used inside the drive to reduce potential sources of particulate generation. But no volume manufacturing operation can produce completely contamination-free product, and the migration to pseudo-contact recording has significantly increased sensitivity to contamination.
In light of the foregoing, there exists a need for a system and method for periodically cleaning a recording head as passes over the surface of the magnetic disk, without materially degrading the performance of the disk drive.